New aerial system radiating several beams



1963 J. R. MOREAU ETAL 3,102,265

NEW AERIAL SYSTEM RADIATING SEVERAL BEAMS Filed Jan. 4, 1960 3Sheets-Sheet 1 INVENTORS: JEAN MOREAU, ROGER SALOMON ALFANDARI,

THEIR ATTORNEY.

Aug. 27, 1963 J. R. MOREAU ETAL 3,102,265

NEW AERIAL SYSTEM RADIATING SEVERAL BEAMS 5 Sheets-Sheet 2 Filed Jan. 4,1960 INVENTORS:

JEAN MOREAU ROGER SALOMON ALFANDARI, BY WM fi/M THEIR ATTORNEY.

1963 J. R. MOREAU ETAL 3,102,265

NEW AERIAL SYSTEM RADIATING SEVERAL BEAMS 3 Sheets-Sheet 3 Filed Jan. 4,1960 FIG.5.

INVENTORSZ JEAN MOREAU, ROGER SALOMON ALFANDARI BY W THEIR ATTORNEY.

rates Unite The invention relates to Wave radiating systems employingseveral antennas, each radiating a beam of energy of differentpolarization.

In the electrical arts, the solution of certain technical problemsinvolves the use of radiating systems with more than two antennas, eachserving distinct functions. For example, in obstacle detection systems arotary aerial system radiating more than two flat beams is used.

Heretofore, antennas have made use of a source associated with anelongated, preferably elliptical, reflector where the ratio betweenlength and cross dimensions is comparatively great.

It would be possible to build a radiating system with more than twoantennas, each radiating a flat beam, by Superposition of simpleantennas with source and reflector as described above. Such a radiatingsystem would be bulky, particularly if the flat beams to be radiatedcannot be parallel.

The object of the invention is to designa system-radiating more than twoflat beams, which is not too. bulky.

A further object is to provide at least one pair of orthogonallypolarized waves from reflectors which are fed with waves that are notorthogonally polarized.

It is a further object of this invention to provide a plurality of wavesof desired relative polarization from waves available from sources wherethe available waves have. a different relative. polarization.

It is a further object of this invention to improved wave processingarrangement.

Briefly, in accordance with one embodiment of the invention reflectorsof an antenna array produce two waves respectively, whose polarizationplanes are perpendicular although the polarization planes of the wavesemitted by the sources associated with such reflectors are notperprovide an pendicular angle 2}? (FIG. 4). 'In front of at least oneof the sources a polarization shift network is provided to make thepolarization planes of the wavesreaching the reflectors perpendicular.It is known that the polarization plane of the waves emitted by such apolarization shift network is different from the polarization plane ofthe incident waves entering the polarization shift network from thesource. If the angle between the slope of the parallel elements of thepolarization shift network and the polarization plane of the incidentwaves is or, the rotation angle of the polarization plane of these wavesis 20:. The angle formed between the polarization planes of the wavesreceived by the reflectors isthus 2oc+2}3. In order that this angle havethe desired value, the condition u+fi=45 must prevail. In case apolarization shift network is provided in front of each source, on and abeing the angles formed by the elements of the polarization shiftnetwork with the polarization planes of the emitted waves, the conditionchanges to a+oz'+fl=:45.

If the radiating system covered by this invention has only two antennas,that is to say in the simplest case, the

second antenna can be identical with the first; it can also While thenovel and distinctive features of the inven- 3 ,lfl'2,265 Patented Aug.27, 1963 "too tion are particularly pointed out in the appended claims,a more expository treatment of the invention, in principle and indetail, together with additional objects and advantages thereof, isafforded-by the following description and accompanying drawings inwhich;

FIG. 1 is a view in perspective of an aerial system with a dual antennaand a simple antenna for a radio detection system with three beams. Theaerial is protected against weather influences by an inflatable radomeshown in partial cutaway representation,

FIG. 2 is a view in larger scale of one of the sources of the dualantenna used according to the invention,

FIG. 3 is a schematic rear view of the reflectors of the radiatingsystem shown in FIG. 1, as seen by an observer looking in the directionof arrow A (FIG. 1),

FIG. 4 is a schematic front view at a different scale of the sourcesprovided in front of the reflectors.

It will be noticed that in FIGS. 1 and 2, the. respective orientationsof the two reflectors and two sources of the dual antenna differ fromthose shown in FIGS. 3 and 4, due to the fact that the former arerelated to a front view whereas the latter relate to a rear view.

FIG. 5 is a schematic rear view of an aerial system with four antennas,and

FIG. 6 is a schematic front view at different scale of the sourcesprovidedin front of the reflectors.

Theaerial system 1 of FIG. 1 is supported by apedestal 2 with three legsand protected against weather influences, for example by means of aninflatable radome 3. It consists essentially of three antennas 4, Sand'6. These are formed by threereflectors 7, 8, and 9-,connectedrespectively to the three feeds. or waveguide, horns 10, 11.and 12, fed by guides 13, 14, 15, one end of which ends at thedistributor 16. The assembly of reflectors 7, 8 and 9 is supported by ajointed structure 17 attached to turntable 18. t

The surfaces of the three reflectors 7, 8, 9 (FIGS. 1 and 2) are partsof paraboloids of revolution with elliptic boundary lines. The longtransverse axes of reflectors 7 and 8 form an X; they .are slightlyinclined in relation to a horizontal line and between themselves form anangle 25 which is also the angle of the short transverse axes. The partsof the reflectors which overlap are formed by an array (19 or 20) ofparallel elements (wire, rods or strips). The elements of array 19 ofreflector 7 are parallel to a direction which'is inclined against thevertical at an angle of 45; they are furthermore perpendicular to theelements of .array 20. These evidently are also inclined 45 to thevertical. The third reflector 9, of which the long axis is horizontal,is of the classic type.

FIG. 2 shows the horn or waveguide feed 10' connected with reflector 7.Assuming that the metal cover has been lifted, it will be noted thatthis wave guide feed is identical with source 11, connected withreflector 8. Essentially, this source is formed by three flat flares 21,22, 23 where the small parallel sides are trapezoidal, whereas the largesides are rectangular. connected with the feed guide 13 by means of twoTs, 214 and 25, and an elbow 26. The three flares radiate waves whosepolarization planes are parallel to the small cross axis of reflector 7.A half-wave network 27, commonly referred to as a polarization changer,is arranged in front of the flares to rotate the polarization plane ofthe waves reaching reflector 7 so that it is parallel withthe elementsof array 19. If a wave is incident at an angle a to the plates of thenetwork, the exit wave occurs at an The flares are I planes are parallelto the long transverse axes AA and BB of the spouts of the feeds (FIG.4); these axes form an angle 213. In FIG. 4 are seen the elements 29 and29 of the half-wave networks 27 and 27', arranged before sources and 1drespectively. As already stated, these networks make it possible toimpart the desired polarization to the waves received by the reflectors.As can be seen in FIG. 4, the planes of the elements of the network andthe polarization plane of the received waves form' an angle a. Feed 12connected with reflector 9' is arranged below feeds 10 and 11, itssymmetrical plane being vertical. This feed 12 is analogous to feeds 10and 11, but has no polarization shift network. An antenna such as justdescribed can be used 'in a'radio detection system of the type employedto detect and measure the angular position of remote objects withrespect to the antenna.

FIGS. 5 and 6 relate to an aerial system having four antennas; theycorrespond to views similar to those shown in FIGS. 3 and 4. It showsthat this aerial system 30 has two dual antennas 31 and 32. Each ofthese antennas is analogous to the dual antenna of FIG. 3. Reflectors33, 34 of aerial system 31, and the reflectors 35, 36 of aerial system32, consist in part of an array. The parallel wave reflecting elementsof each of them are inclined by 45 to the vertical. With the reflectors33-34 and 3536 areconnected feeds 38--39 and 4tl41, identical, for

1 example, with that shown in FIG. 2. Before each feed is arranged apolarization shift network 41, 42, 43 or 44, with characteristicsdetermined according to the principles shown above.

While the principles of the invention have now been made clear, therewill be immediately obvious to those skilled in the art manymodifications in structure, arrange- 'ment, proportions, the elementsand components used in the practice of the inventiom'and otherwise,which are particularly adapted for specific environments and operatingrequirements without departing from those principles. The appendedclaims are therefore intended to cover and embrace any suchmodifications within the limits of the true spirit and scope of theinvention.

What we claim and desire to secure by Letters Patent of the UnitedStates is:

1. An arrangement for communicating electromagnetic waves with a firstand second polarization separated 90 from one another comprising a firstand second electromagnetic wave reflector, each of said reflectorshaving a major and a minor axis, means for mounting said reflectors in across position such that their major axes make a given angle withrespect to one another, each of said reflectors having a plurality ofparallel electromagnetic wave reflecting elements at least where thereflectors overlap one another, the elements of one reflector beingperpendicular to the elements of the other reflector, a first waveguidehorn associated with said first reflector, a second waveguide hornassociated with said second reflector, each of said horns having majorand minor horn axes, said major axis of each horn being positionedparallel to the minor axis of the associated reflector, said given anglebeing different from 90 such that electromagnetic waves communicatedbetween one horn and its associated reflector are not perpendicular tothe electromagnetic waves communicated between the other horn and itsassociated reflector, means for rotating the polarization ofelectromagnetic waves associated with said first horn such that theresulting electromagnetic waves are polarized parallel to the elementsof said first reflector, means for rotating the polarization ofelectromagnetic waves associated with said second horn such that theresulting electromagnetic waves are parallel to the elements of saidsecond reflector, a third electromagnetic wave reflector having a majorand minor axis, a third horn associated With Said third. reflector andhaving a major and minor horn axis, said major axis of said third hornbeing parallel to the minoraxis of said third reflector, said major axisof said third reflector positioned to be parallel to the line bisectingthe major axes of said first and second electromagnetic wave reflectors,and means for angularly rotating said feeds and associated reflectorsabout a common axis.

2. An arrangement for providing electromagnetic waves with-a first andsecond polarization separated from one another comprising a first,second, third, and fourth electromagnetic wave reflector, each of saidreflectors having a major and a minor axis, means for mounting saidrefleotors in pairs such that their major axes make different givenangles with respect to one another and with respect to said'desiredangle, each of'said reflectors having a plurality of parallelelectromagnetic wave reflecting elements at least where they overlap theother reflector in said pair, the elements of each reflector in eachpair being perpendicular to the elements of the other reflector in suchpair, first, second, third and fourth waveguide horns associated withsaid first, second, third and fourth electromagnetic wave reflectorsrespectively, each of said horns having major and minor feed axes, saidmajor axis of each horn being positioned parallel to the minor axis ofthe associated reflector, individual means associated with each of saidfirst, second, third and fourth horns for rotating the polarization ofelectromagnetic waves associated with such horns such that the resultingwaves are polarized parallel to the elements of the reflectorsassociated with each of said horns.

3. An arrangement for transmitting electromagnetic waves with a firstand second polarization separated 90- from one another comprising afirst and second electromagnetic wave reflector, each of said reflectorshaving a major and a minor axis, means for mounting said reflectors in across position to form an X configuration, each of said reflectorshaving a plurality of parallel electromagnetic wave reflecting elementsat least in the overlapping sections of said configuration, the elementsof one reflector being perpendicular to the elements of the otherreflector, a first electromagnetic wave feed associated with 'said firstreflector, a second electromagnetic wave feed associated with saidsecond reflector, each of said feeds having major and minor feed axes,said major axis of each feed being positioned parallel to the minor axisof the associated reflector, means for rotating the polarization ofelectromagnetic waves emanating from said first feed such that theresulting electromagnetic waves are. polarized parallel to the elementsof said first reflector, means for rotating the polarization ofelectromagnetic waves emanating from said second electromagnetic wavessuch that the resulting electromagnetic waves are parallel to the ele-References Cited in the file of this patent UNITED STATES PATENTS2,790,169 Sichak Apr. 23, 1957 FOREIGN PATENTS 668,231 Germany Nov. 28,1938 1,141,476 Pittman Sept. 3, 1957 1,219,321 France Dec. 28, 1959

1. AN ARRANGEMENT FOR COMMUNICATING ELECTROMAGNETIC WAVES WITH A FIRSTAND SECOND POLARIZATION SEPARATED 90* FROM ONE ANOTHER COMPRISING AFIRST AND SECOND ELECTROMAGNETIC WAVE RELECTOR, EACH OF SAID REFLECTORSHAVING A MAJOR AND A MINOR AXIS, MEANS FOR MOUNTING SAID REFLECTORS IN ACROSS POSITION SUCH THAT THEIR MAJOR AXES MAKE A GIVEN ANGLE WITHRESPECT TO ONE ANOTHER, EACH OF SAID REFLECTORS HAVING A PLURALITY OFPARALLEL ELECTROMAGNETIC WAVE REFLECTING ELEMENTS AT LEAST WHERE THEREFLECTORS OVERLAP ONE ANOTHER, THE ELEMENTS OF ONE REFLECTOR BEINGPERPENDICULAR TO THE ELEMENTS OF THE OTHER REFLECTORS, A FIRST WAVEGUIDEHORN ASSOCIATED WITH SAID FIRST REFLECTOR, A SECOND WAVEGUIDE HORNASSOCIATED WITH SAID SECOND REFLECTOR, EACH OF SAID HORNS HAVING MAJORAND MINOR HORN AXES, SAID MAJOR AXIS OF EACH HORN BEING POSITIONEDPARALLEL TO THE MINOR AXIS OF THE ASSOCIATED REFLECTOR, SAID GIVEN ANGLEBEING DIFFERENT FROM 90* SUCH THAT ELECTROMAGNETIC WAVES COMMUNICATEDBETWEEN ONE HORN AND ITS ASSOCIATED REFLECTOR ARE NOT PERPENDICULAR TOTHE ELECTROMAGNETIC WAVES COMMUNICATED BETWEEN THE OTHER HORN AND ITSASSOCIATED REFLECTOR, MEANS FOR ROTATING THE POLARIZATION OFELECTROMAGNETIC WAVES ASSOCIATED WITH SAID FIRST HORN SUCH THAT THERESULTING ELECTROMAGNETIC WAVES ARE POLARIZED PARALLEL TO THE ELEMENTSOF SAID FIRST REFLECTOR, MEANS FOR ROTATING THE POLARIZATION OFELECTROMAGNETIC WAVES ASSOCIATED WITH SAID SECOND HORN SUCH THAT THERESULTING ELECTROMAGNETIC WAVES ARE PARALLEL TO THE ELEMENTS OF SAIDSECOND REFLECTOR, A THIRD ELECTROMAGNETIC WAVE REFLECTOR HAVING A MAJORAND MINOR AXIS, A THIRD HORN ASSOCIATED WITH SAID THIRD REFLECTOR ANDHAVING A MAJOR AND MINOR HORN AXIS, SAID MAJOR AXIS OF SAID THIRD HORNBEING PARALLEL TO THE MINOR AXIS OF SAID THIRD REFLECTOR, SAID MAJORAXIS OF SAID THIRD REFLECTOR POSITIONED TO BE PARALLEL TO THE LINEBISECTING THE MAJOR AXES OF SAID FIRST AND SECOND ELECTROMAGNETIC WAVEREFLECTORS, AND MEANS FOR ANGULARLY ROTATING SAID FEEDS AND ASSOCIATEDREFLECTORS ABOUT A COMMON AXIS.